The present invention relates to variable resistors and, more particularly, to variable resistors suitable for use in tone control.
Generally, in such devices as stereo amplifiers, two kinds of variable resistors are used for adjusting high and low pitched tones, respectively. The arrangement is such that the levels of the high and low-pitched tones are increased or decreased as the slides of the variable resistors are rotated. When the slides are set at the intermediate positions on the resistances of the respective variable resistors, for obtaining intermediate tone levels, it is preferred that the increase and decrease of the level at high and low-pitched tones are avoided to realize a flat characteristic.
However, as a matter of fact, the physical intermediate position on the resistance often does not coincide with the electrical intermediate point, because of the fluctuations of the characteristics of resistances, capacitors and other electric parts incorporated in the tone control circuit, as well as the fluctuation of the characteristic of the variable resistor itself. For the above and other reasons, undulation of level at the intermediate position is likely caused, resulting in the fluctuation of frequency characteristics and tones.